TechPractices are outstanding housing projects throughout the U.S. where innovative technologies are implemented. Builders and remodelers can use these examples as models for projects of their own.
|EcoVillage at Ithaca Snapshot
||Architect/Builder/Developer: Jerold Weisburd Coterre
||30 units in duplex houses
||$90,000 to $170,000 for 900 to 1,700 square feet, respectively
||Cooperative. Residents own shares of the overall development
||Ventilation control system; water heaters with space heating capability; plumbing for greywater reuse; gas service submetering; open systems concept.
As a PATH website visitor, you probably know something about
sustainability, taking into account future generations when building
homes today. By using an inventive arrangement of distribution
systems, homes can be designed and constructed to generate low
energy bills but maintain high indoor air quality. Internal home
wiring systems also can economically accommodate future communication
innovations such as high-speed internet and intranet.
In upstate New York, a group of families got together to build
an environmentally responsible community that would use advanced
energy systems while keeping home prices modest. There are a total
of 15 duplex houses (30 units) located close to town to reduce
transportation time and costs. By including a large, extra community
house with spaces all residents could use--such as woodshop, soundproof
music room, and kids' playroom-- individual houses could
be slightly smaller. This common house has its own climate system,
featuring geothermal heat pumps with the heat exchange piping in a pond instead
of the earth, and a radiant floor heating system.
The group felt it was important that each household be responsible
for its own energy use. This is a common issue in multi-family
housing, and the experiences of EcoVillage have important implications
for shared systems in clustered housing and apartment buildings.
The standard way to assess energy responsibility is to individually
meter each apartment. The group realized, however, that this would
negate some of the energy savings because the utility would charge
each homeowner a monthly metering fee. So the designers devised
a "mini-district" submetering system that would use
only five metered utility connections and measure each of the
30 residents' energy use internally. Each metered connection
serves a pair of small gas-fired boilers, which feed space heating
and domestic hot water coils for six to eight households in each
Since the boilers would provide for both space heating and
hot water, the designers saw an opportunity to further reduce
equipment costs by sizing the boilers according to peak domestic
hot water demand. The homes are so efficient that, even in upstate
New York, energy needed for space heating is less than that for
domestic hot water. The maximum combined load of showers and space
heating is 500,000 BTU per hour per boiler. By taking advantage
of slow heat loss due to thick insulation, the designers specified
boilers with 320,000 BTU per hour capacity, considering it rare
that everyone would shower at the same time on the coldest days.
An economical submeter system that measures only run time of individual
residents' pipe circuit was designed and installed. The meters
measure total energy use as well as the use of energy specifically
for domestic hot water.
Densely-packed cellulose wall insulation, vapor barrier, and
triple-glazed windows help create nearly airtight homes. Thus,
indoor air quality (IAQ) is an important issue. By incorporating
a fresh air intake into the return air ducts, the air distribution
system provides filtered fresh air in every room, even if doors
and windows are closed. In addition, placing boilers in separate,
insulated sheds keeps combustion away from living spaces.
To take advantage of the rapid technological development in
HVAC and communications distribution, the community opted for
an "open systems concept." Pipe chases connecting houses
through crawl spaces contain plumbing and heating, electrical,
telephone, and cable service, and allow easy routing for future
repairs and upgrades. The designer/builder considers the chases
to result in cost savings by eliminating trenching. The residents
had the opportunity to take advantage of the open systems concept
soon after it was installed by adding an ethernet local area network
and high speed Internet wiring, which they installed themselves.
Some residents chose the Category Five Wiring system.
The designer/builder developed an exterior wall that uses the
performance advantage of dry blown cellulose insulation under
compression. Although 2 by 6 studs are used, the assembly resists
heat loss almost as well as 8-inch thick walls. This is accomplished
with 2 by 2 horizontal strapping along the 2 by 6 studs, which is
separated by a durable vapor barrier. The cellulose is overblown
through holes in the barrier to create a pillowed effect. It is
held back by the strapping, which becomes a wire chase. Therefore,
approximately two-thirds of the wall is insulated to 7.25 inches instead of 5.5 inches. Some air space is created between the vapor
barrier and the sheetrock so wiring does not penetrate the vapor
barrier. The combination of tight construction, densely-packed
insulation, and triple-glazed windows also decreases sound transmission,
resulting in a sense of privacy -- an important issue in clustered
In the beginning, the local bank would not consider cooperative
financing because officials there were unfamiliar with it. However,
with persuasion from the developer and a requirement for 20% down
payment, they approved financing. At $90,000 to $170,000, these
homes are slightly below the area median. Energy bills, however,
are much lower than average homes in the area, making it economical
to live in EcoVillage.
It is generally recognized that making households accountable
for energy use results in significant savings. EcoVillages
mini-district heating system reduces metering costs. Submetering
also saves each household roughly $15 per month, up from $7 per
month a few years ago due to deregulation.
Local code considers houses of three stories or more to be
multiple dwellings (which would activate fire/egress restrictions),
prompting the decision to limit EcoVillage to two-story buildings.
Therefore, a first floor mezzanine was provided above the kitchen
to offer additional living area within two stories.
The open systems method complies with code, but the municipality
would not allow the builder to run sanitary lines through the
large diameter pipes in the crawlspace walls. This would have
saved considerable excavation, particularly since each house is
double plumbed for greywater/blackwater
separation. They were, however, allowed to branch to each
pair of buildings through a shared sewer connection (15 instead
of 30), and to limit clean outs to one per group of buildings
due to the linear site plan.
Monitoring system performance after move-in proved instructive.
For example, specifying even smaller boiler pumps and timer controls
on fans would have further reduced energy consumption. The small
boilers proved adequate, though there have been some complaints
on cold mornings when multiple showers occur just as the heat
is timed to turn on. This was resolved by resetting the timer
The domestic hot water submetering system tracking run time
was thought to be adequate. It was chosen based in part on cost,
but it turns out to be less than accurate, because it assumed
similar setpoints among households. The problem is, households
set their hot water thermostats at different temperatures. In
addition, the sensors have proven to be maintenance intensive.
The energy consultant plans to retrofit the community with a new
set of submeter sensors that measure temperature drop as well
as run time, and cost much less than conventional BTU submeters.
The sensors will also enable zoning between the north and south
sides of the houses -- important to making homes with high solar
gain more comfortable. These sensors include software that automatically
produces energy bills for each house.
In the winter, there is some warm air stratification due to
convection under the 16-foot high ceilings at the mezzanines. Locating
the cold air returns high at the mezzanine and low at the ground
floor could have reduced temperature extremes. A big advantage
of the high ceiling is the cooling stack effect it creates. Not
one resident has bought an air conditioner. They keep cool with
ceiling fans and window exhaust fans, with just a few very hot
summer days driving them to the air conditioned "common house."
Despite high controlled ventilation rates in the houses of
almost 2.5 air changes per hour, designers believe they could
further improve IAQ by installing low-pressure exhaust ports in
closets, under sinks, and in garbage cabinets.
The project has received a good deal of press, and has been
featured on CNN, Nickelodeon, and National Public Radio. Feature
articles on EcoVillage have been published in the New York
Times and Popular Science. The community has been covered
in numerous other publications, including American Demographics,
the Washington Post, and the Wall Street Journal.
It also won a Building Innovation for Homeownership award from
HUD in 1996.
Do you have a specific question? Try the contacts listed below:
Building Performance Contractors Association
121 Rachel Carson Way
Ithaca, NY 14850
EcoVillage at Ithaca